Organic EL displays known in the prior art include bottom-emission type displays, in which an organic EL emission panel is formed directly on a color conversion filter panel, and top-emission type displays, in which a separately manufactured color conversion filter panel and organic EL emission panel are bonded together, with the emission region of the organic EL emission panel and the color pattern formation region of the color conversion filter panel opposed, and with a transparent resin filler material.
As shown in FIG. 1A to FIG. 1C, an example in the prior art of a top-emission type display is configured with the emission face of an organic EL emission panel 10 opposed to the light-receiving face of a color conversion filter panel 20, bonded together with a prescribed interval maintained by spacers 60, and with the entire layered structure portion formed by the organic EL emission panel 10 and color conversion filter panel 20 sealed by a peripheral seal member (not shown).
An organic EL emission panel 10 normally is formed using a plurality of reflective electrodes 120 formed on an organic EL emission panel substrate 100 with an underlayer 110 intervening, an insulating layer 111 layered above and between the reflective electrodes 120 with opening portions provided on the reflective electrodes 120, an organic EL layer 130 including an organic emission layer layered on the opening portions and insulating layer 111 on the reflective electrodes 120, a plurality of transparent electrodes 140 facing the reflective electrodes 120 above the opening portions of the reflective electrodes 120 on the organic EL layer 130 and connected to wiring on the panel peripheral portion, and a transparent inorganic barrier layer 150 which covers the transparent electrodes 140 and organic EL layer 130.
On the other hand, as shown in FIG. 1A to FIG. 1C, a color conversion filter panel 20 is formed of a color filter 210 and black matrix 211 formed in stripe shapes on a transparent substrate 200, as well as a color conversion layer 220 layered on the color filter 210.
The peripheral portion of the organic EL emission panel 10 and color conversion filter panel 20 is sealed by a peripheral seal member, and the organic EL layer 130 and color conversion layer 220 are cut off from contact with outside air and with water in particular, and are protected. Further, in general spacers 60 are placed between the organic EL emission panel 10 and color conversion filter panel 20 for fine adjustment of the interval between the organic EL emission panel 10 and the color conversion filter panel 20.
In the prior art, in order to form the color filter 210 and color conversion layer 220 of the color conversion filter panel 20 in patterns, a photolithography method has been adopted. However, as a method enabling effective utilization of the materials used in color filters and color conversion layers, and also enabling application and fault repair in subpixel units, a formation method using an inkjet method has been proposed in Japanese Patent Application Laid-open No. 2004-288403 (see Patent Reference 1).
Further, as a method of preventing color mixing between subpixels during formation of a color filter 210 and color conversion layer 220 using an inkjet method, WO 06/54421 proposes a method in which, as shown in FIG. 2, each subpixel is enclosed by barrier walls 221 formed by a vertical-horizontal mesh-shape thick film, an inkjet method is used to cause impact of a minute amount of a dye-containing ink within each enclosed subpixel, and heating and drying are performed to form a color filter 210 and color conversion layer 220 (see Patent Reference 2). In WO 06/54421, there is no description of bonding together of a color conversion filter panel 20 and organic EL emission panel 10 with resin filler material.
In the prior art, the space between the organic EL emission panel 10 and the color conversion filter panel 20 is filled with nitrogen or another gas or inert liquid. However, whereas the refractive index of the transparent electrodes 140 is approximately 2.0, and the refractive indexes of the color conversion layer 220 and color filter 210 are approximately 1.5, the limits to the refractive indexes of nitrogen and other gases is 1.0, and the limit to the refractive indexes of inert liquids is approximately 1.3. As a result, the difference in refractive indexes of the filling gas or inert liquid and the constituent layers adjacent thereto is large, and so the efficiency of light extraction has not been very good.
In recent years, as means for improving the efficiency of light extraction, methods have generally been adopted in which epoxy-base adhesives and other transparent resins having a refractive index of 1.5 or higher, approaching the refractive indexes of the transparent electrodes 140 and barrier layers 150 of organic EL emission panels 10, and the color conversion layers 220 and color filters 210 of color conversion filter panels 20, are used for filling.
Resin filler materials comprising an epoxy-based adhesive or other transparent resin, used in bonding together an organic EL emission panel 10 and a color conversion filter panel 20, have high viscosity compared with liquid filling materials and poor spreading over the entire bonding face. When a color conversion filter panel 20 and organic EL emission panel 10 manufactured using the method described in WO 06/54421 are bonded together with a resin filler material 40, air bubbles 500 remain in regions demarcated by the barrier walls 221 at positions at which the resin filler material 40 is dropped, as shown in FIG. 3, and so the entire region in which adequate bonding is required cannot be filled with the resin filler material 40. At the portions of the air bubbles 500, the efficiency of light extraction is reduced due to the difference in refractive index, and luminance unevenness results. Also, as shown in FIG. 3, air bubbles 500 occurring in dropped portions cannot be adequately removed in vacuum due to the high viscosity of the resin filler material, and may expand and spread considerably during evacuation and during heating and hardening of the resin filler material.
Further, in methods of bonding by dropping a general liquid filler material in vacuum, adopted in bonding of liquid crystals and similar, the liquid filler material does not spread uniformly to the corners of the screen region, and there are cases in which luminance unevenness and similar occur. Specifically, as shown in FIG. 4, bonding is performed after dropping and after depressurizing the atmosphere, and so spreading of the liquid filler material can be expected to a certain extent. However, the resistance of the barrier walls 221 is considerable, and a large amount of time is required for the liquid filler material to spread to the corners of the screen region. Further, there is also the possibility that the liquid filler material may not spread completely.                Patent Reference 1: Japanese Patent Application Laid-open No. 2004-288403        Patent Reference 2: WO 06/54421        